Universal multidogging device



Jan. 9, 1945. w. J. NIGHTINGALE 2,367,945

UNIVERSAL MULTIDOGGING' DEVICE I Filed July 17, 1943 v 2 Sheets-Sheet l 92 .94 p d ,4 @E

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A TTORNEW- Jan. 9, 1945.

W. J. NIGHTINGALE UNIVERSAL MULTIDOGGING DEVICE Filed July 17, 1943 2 Sheets-Sheet 2 v e v 4. N Z 0 34% PatentedJan. 9, 1945 William J. Nightingale, Oak Park, n1., assignor of one-half to George 0. Bruen, Chicago, Ill.

Refiled for abandoned application Serial No. 309,464, December 15, 1939. This application July 17, 1943, Serial No. 495,141

14 Claims.

I The present invention relates to machine tools and particularly relates to dogging devices for use with machines, such as lathes; this application constituting a refiling of my application for U. S. patent, Ser. No. 309,464, filed December 15, 1939, and subsequently forfeited.

I In metal working, the prior common method of driving centered work in a lathe is with the use of asingle tail dog. Such dog is generally L- shaped, having the leg thereof clamped to the work which projects through an opening therein,'with the tail of thedog received within a radial slot provided in a face plate on the lathe. I

This prior method has several disadvantages, one of them being that it is diflicult to accurately centerthe work because the tail may strike the bottom of the slot before the work is fully in place on the center.- The Work should always be accurately centered on the points of the lathe centers and not be crowded to one side, as accurate work is impossible under these conditions. A straight-tail dog can be used, but this necessitates a driving stud in the face plate. Another disadvantage of .this priormethod is that it is necessary'to keep on hand a. plurality of dogs, making up a set, for the accommodation of different size work, since each dog is only capable of use within a slight range of work size. It is therefore necessary to use difierent sized dogs for correspondingly different size work. The set-up time in changing work and changing dogs on the machine is considerable and represents a production loss. a

In certain types of machine operation only one end of the piece of work is supported on the live or spindle center and the other end is supported in a steady rest. Dogs of the type mentioned above have been used; and the work is held against the live center by a bridle or strap having the ends thereof fixed to the face plate to pull the dOg thereagainst. This is an unsatisfactory and makeshift method. s

One of the primary objects of the present invention is to provide an improved do ging device of such a character that it may be mounted on a lathe and need notbe removed therefrom when changing workpieces, even though such changesin work involve differences in ize of the pieces worked on, thereby saving considerable productive time.

Another object of the invention is to provide an improved dogging device of such a character that a single unit may be used throughout the range of workpiecesizes that heretofore has required a complete set of dogs of the prior type mentioned above, thereby effecting considerable savings in money and productive time.

Another object of the invention is to provide a dogging unit which serves to accurately clamp the work on center and which eliminates the necessity for the face plate required when using dogs of the prior type mentioned above.

Another object of the invention is to provide a dogging device of such a character that the work may be mounted on centers in less time with the assurance that the work will not be crowded to one side of the center.

Another object of the invention is to provide a dogging device of such a character that it is self-centering, and slip-proof, thereby providing I a balanced drive which reduces tool breakage.

- throughout;

Another object of the invention is to provide a dogging device which eliminates the use of the bridle or strap when one end of the workpiece is supported in a steady rest.

Another object of the invention is to provide an improved dogging device in which the clamping means thereon are so constructed and balanced that they inherently exert equal pressures on opposite sides of the workpiece so that the workpiece will not be shiftedoff center when the Figure 1 is a fragmentary side elevational view of a metal working lathe, using a steady rest, and employing a dogging device according to the pres I ent invention;

Figi 2 is an end elevational view of the dogging device illustrated in Fig. 1, taken substantially along the line 2-2 thereof;

Fig. 3 is an enlarged cross-sectional view taken substantially along the line 3--3 of Fig. 2 and showing the dog attached to the lathe driving spindle;

Fig. 4 is a cross-sectional view taken substantially along the line 4-4 of Fig. 3;

Fig. 5 is a cross-sectional view, on a reduced scale, taken substantially along the line 5-5 of of the structure illusthe lathe l0, and is adapted to support a piece of. metal stock 16, adjacent one end thereof, which.

is the piece being worked upon. A unitary do ging device, according to the present invention; is generally indicated at 18, and is mountedon the live spindle l2 in driving relationship therewith. Y o

One of the lathe center point elements is indicated at 20, and is associated with the live spindle l2 in the usual way and projects inwardly therebeyond, Another lathe center point element, not shown, is also on the lathe in alignment with the element in the usual way. In the illustrated embodiment'of the invention, the work piece [6 is shown as 'havingone end thereof mounted on a steady, rest, but it is to be understood that the present invention is equall adapted to the type of work when both ends of the stock It would be centered on the'center points of the lathe in the usual way.

The present invention is primarily concerned with the construction and'operation of" the do ging device l8, and such dogging deviceis adapted for use whether both ends of the stock ar centered or whether one end is centered and the other end supported within a steady rest, as mentioned above. cludes a supporting plate member 22 having a central hub portion '24 of greater thickness than the major portion thereof with side portions projecting radially outwardly therebeyond at *d-iametrically opposed positions. The supporting member 22 issuitably mounted onthe live spindle l2 so that upon driving of the spindle the do unit I8 is driven thereby. In the embodiment illustrated, the hub portion -24 is provided with :a central aperture therethrough which is threaded so that the support is threadably received over the threaded end of the spindle l2.

The member 22 is provided with openings 26 therethrough in the side portions adjacent the outer ends thereof, the axis of such openings being substantially parallel to the line between the lathecenter points or the center line axis of the stock 1'6 when such stock is in its properly centered position.

A generallyrectangular mounting member 281s mounted to'said supporting member 22 adjacent one of the outer ends thereof, and such mounting member includes a generally rectangular aperture 30 therein with an integral pin' portion 32 The pin at the mid point of one side thereof. portion 32 is slidably received within one of the openings 26 and is so fixed with respect thereto that'the rectangular member 28 may move toward and from the supporting member 22 and also turn about the axis of the pin 32 with respect to the supporting member. Therectangular member 28 is positioned on the front side'of the supporting member, and the, connection is such that such member 28 isresilientl urged toward the supporting member 22. The connection for the mounting member 28 includes a spiral spring 34 having one endthereof received over an annular shoulder 38 formedintegral with .themem- The dogging device l8 inplate 22.

- Another mounting block 42 has a central circular opening 44 formed therein and has a substantially straight inner edge which is adapted to abut a-gainst'the'race of the supporting mem- -ber22 adjacent thatend opposite to that to which the member 28 is mounted. The block 42 has an integral stem'portion 46, similar to the stem portion 32, above described, which is slidably received through the opening 26 at such opposite end. The block 42 is resiliently mounted with respectto the supporting member by meansof a coil spring 34 and a retainer cap 38, which. are disposed in the same relationship as that described above in connection with the resilient mounting for the member 28.

A floating. bar 48 is provided which has a central hub portion 50 withan aperture 52 therethrough so that the center point element 20 .proje'cts through the aperture 52 beyond the bar-48 .to aposition such asthat illustrated in Fig. 3 when the parts are assembled. One of the ends of the bar member-48 is slidably received within opening 440i supporting block 42. The other end of the bar 48 isslida'bly received within anaperture 54' formed in a bearing block member 56 (Figs. 3 and 8). The block "56 is generally rectangular in form and has a width substantially equal to the width of the rectangular aperture 30 in member 28, but is of a length less than the length of suchaperture 30 so that the block member 56 is slidable with respect to the block member 28. The block member 28 is provided with aligned apertures 58 therethrough; and oppositely disposed guide pins 60 are threaded into the block 56 and .are adapted to project through the apertures '58. The apertures 58 are larger than the .pins'EO so that there may be freedom-of movementbetween the block member :56 and the member 28, but the pins ".60 are ,of such a length that the block member will be prevented from falling out "of its position with respect to the member 28.

It will thus be seen that the bar 48 is 'free to slide, in a direction along its length, with respect to 'thersupporting member '122, and also that one end of the bar member 48 ma slide'transversely of "the member 22 while .both ends can pivot with respect thereto. Also, the bar rmay .be moved away from the plate "member 22 against the resistance of springs 34. A floating 'mounting :is thus provided for the bar 4.8rwith respect to the supporting member 22..

In order to limit. the extent towhichthe barF lB may move along its. length with respect to the support 22 so that its tends will not drop out of the member 42 and, projections j5l1'are formed integral with the hub portion 50. Stop pins .59 are'fixed to the frontface ofmember 22 between the projections 51, so that such projections will.

opposite sides of the central portion thereof to provide facing jaws which are adapted tov clamp againstthe workpiece I6. The jaws are generally L-s'haped, and have circular openings 84 formed I in the leg portions thereof. Such openings 64 are I of substantially the same diameter as the diameter of the bar 48 and are adapted to slide therealong so that'they are movable toward and away from each other.

In order that the present unit may be used with a wide range of stocksizes and may be used to replace a complete set of the prior type dogs discussed above, the jaws 62 are so mounted and may be fixed withrespect to each other at a plurality of points along the length of the bar 48 between the mounting blocks 28 and 42. ,In order to adjustably fix the jaws 62 with respect to the bar 48, aback-up plate66 is provided for each the legs of jaws 62. Each of such plates 66 has a circular opening .68 formed therein which has adiameter substantially the same as theoutside diameter of bar 48. I r

The backing plate 65 is connected to its adjacent jaw 62 by means of a setscrew 10, which may be of the Allen type and which is threadably received within a tapped opening '12 formed in the plate member 66. The screw It extends radial. v inwardlyand has a reduced portion 14- terminating in an nlargedhead I6 at the inner end thereof. The enlarged head is slidably received within a groove 18 formed inthe jaw 62, which opens through the jaw face of the member 62 and which communicates with another slot 80 of less width than the width of the groove 18 and of substantially the same width as the diameter of thereduced portion 14 of the screw I0. The

reduced portion 14 is, thereby, slidably received within the groove 80 and. the enlarged head is.

slidably received within the groove 18, the groove 18 having a width substantially equal to the width of thehead 16. I

For rough adjustments of the jaws 62 with respect to each other, the backing plates 6% are fixed against axial movement with respect to the bar 48 at any one of a pluralityof positions, there being'three of such positions illustrated for each of'the jaws in the embodiment here described. This is accomplished through the formation of arcuate grooves 82 on the rear side of the'bar 48 and at spaced positions therealong. The bases of such grooves'are preferably formed on a radius substantially equal to the radius of thelaperture 68, and the width of such slots is slightly greater than the width of the plate 66 so that such plate may drop into these grooves and abut against the side walls thereof so that axial movement of the plate 65 with respect to the bar 48 will be prevented. This rough setting of the jaws may be readily accomplished when the jaws are out of by merely disengaging the plate 66 from the particular groove 82 with which it is associated, and then sliding such plate,

engagement withthe stock together with the jaw, along the bar and dropping the plat 66 into the groove desired.

The grooves 82 thickness of the jaws 62, so that such jaws will readily slide over therein. I

For the finer adjustments of the jaws with respect toeach other and for clamping the jaws to the work, it will be appreciated that the'jaws 62 may be moved toward and awayfrom' their re:

the grooves. without dropping of thejaws 62, and is slidably mounted on the bar 48 behind or disposed radially outwardly of spective backing plates by turning' the set screws Ill. I direction will cause the jaws 62 to move away from the plates Eli-through the connection of the enlarged head 16 in the grooves 18,'as the inner face of such'head abuts against the base of the groove 18. The turning of the screws in the opposite direction will cause the jaws to move toward the plate members 66 as the outside surface of the enlarged head 16 will abut against the overhanging edge adjacent the slot and pull the jaws toward their respective backing members66.

In the use or operation of the structure so far described, assuming that the workpiece l6 has been centered on both center points of a lathe,v

' grooves 32 corresponding roughly to the size of One of the screws it is then the workpiece. turned to urge its jaw 52 toward the workpiece to such a position that it is just about in contact with the workpiece. The other set screw on the other plate 66 is then turned so thatits jaws are forced against the workpiece. Since the jaws are fixed with respect to each other through the floating bar 48 and the connection of the members 66 therewith through the grooves 82, and due to the mounting of the floating bar 48, it-will be seen that both of the jaws clamp the workpiece equally and are drawn radially inwardly of the workpiece in exactly equal increments and with exactly the same pressure applied to both sides of the work-' piece. Also, the jaws are self-aligning so that the workpiece is properly engaged. It will thus be evident that the workpiece cannot be pulled off center and that the tightening operation of the lastset screw may be accomplished as rapidly and with as much pressure as desired without in any way disturbing the center of the workpiece.

It also clearly follows that the workpiece l6 may be just as easily and quickly removed from are of a less width than the 0v viously used.

its engagement with the dog without removing the unit l8 from the lathe. of the same or a difierent size maybe. immediately applied to the machine and the positioning of the jaws with respect 'to the new workpiece, whether it be of the same or a different size,

is readily accomplished.

I Thedog unit of the present invention is also so constructed and is provided with such means that the workpiece is held against the live center when the other end of the workpiece is supported in a steady rest, thereby eliminating the need for the make shift bridles or straps pre- In orderpto accomplish this, a cam plate having a central circular aperture 92 formed therein is rotatably mounted on an annular I shoulder 94 formed in the hub portion 24 of the supporting plate 22. Such plate 98 is rotatable on the shoulder 94 with respect to the member 22 and is fixed against axial displacement with respect thereto by means of a thrust ring 96 which is threa'dably received over the rear end of the hub portion 24 and may be fixed against rotation by means of a safety set screw 98.

So that the cam plate 96 ma be rotated with respect to the plate22, handles 99 are fixed to the cam plate 90 in such positions that they'do not interfere with the operation of the dog but Turning of the set screws win one Another workpiece are readily accessible. In order to limit the rotative'movement of the cam member 90 with respect to the support 22, a stop pin IIH may be fixed to the member 22 and projects in the line of rotative movement of the handles 99 so that such handles abut against the pin IOI when they have been turned a predetermined distance.

The cam plate 90 is provided with oppositely disposed cam surfaces I02 ,in the front face thereof which lie adjacent the back face of the side portions of the member 22. Such cam surfaces are in the form of surface recesses of predetermined'slope, sloping from one radial end flush with the face portion of the cam 90 and to relative deepness at the other radial end of the recesses.

Apertures I04 are provided through the supporting member 22 at predetermined radial positions within the confines of the cam plate 90 and slidably receive therein the stems I06 of throwout plungers. Such plungers have enlarged heads I08 integral with the stems I06 which bear against the front face of the member 22. The back ends of stems I06 are rounded and are adapted to bear against the cam surfaces I02 of the cam plate 90. The heads I08 are of such a size that when they are moved toward the floating bar 48 they will abut against the rear edge of the legs of the jaws 62 in whatever position the jaws 62 are along the length of the bar. In the embodiment illustrated there is only one plunger shown for each of the bars. Instead of using a single plunger' for each bar, a plurality of such plungers could be readily disposed on each side of the center so that plungers of a smaller head size could be used with the assurance that the jaws 62 would be engaged in any one of its positions along the length of the floating bar.

Viewing ,Figs. 3 and 4, Fig. 3 illustrates the normal position of the plungers when the jaws 62 are in clamping engagement with the work piece. When the workpiece is supported in a steady rest, as mentioned above, the prior type bridle or strap may be eliminated by the following use or operation of the device of the present invention. The cam plate 90 is normally positioned so that the stems I06 project into the deepest portion of the cam grooves I02. The heads I108 are then not in engagement with the legs of the jaws 62. By then turning the cam plate in the direction indicated by the arrow in Fig. 5, the plungers are thrown outwardly so that the heads I08 bear against the rear edges of the jaws 62 and force such jaws together with the floating bar 48 away from the supporting member 22 against the resistance of springs 34. Such jaws are held in this position until they are clamped to the workpiece in the manner described above. That end of the workpiece engaging the center point 2%) has previously been centered and the jaws are clamped thereto in the same way as that mentioned above so thatthe workpiece is clamped by the jaws for turning the workpiece during those machining operations which are to be performed.

After the jaws have been'clamped to the workpiece, the cam plate is then turned back to its normal position, thus relieving the pressure of the plungers against the jaws. The springs '34 will then act to pull the floating bar 48 back toward the plate-member 22. Since the plate member is axially fixed with respect to the center point 20, it will be appreciated that the workpiece is then pulled against the center point through the action of springs 34 and will be held thereagainst during the machining operation.

Formal changes may be made in the specific embodiments .of the invention described without departing from the spirit and substance of the invention, the scope of which is commensurate with the appended claims.

What I claim asnew and desire to secure by Letters Patent is:

, 1. A dog device adapted for attachment to the live spindle of a lathe having a center point element in which saiddevice clamps a piece of work which has been properly positioned on said center point element comprising a supporting member adapted for driving attachment to said spindle, a bar member, means mounting said bar member on said supporting member transversely thereof so that said bar member is fixed for rotative movement with said supporting member but is at the same time 'slidable transversely of said supporting member, clamping members adapted to clamp said piece of work and mounted on said bar member, and means adjustably fixing said clamping members with respect to each other on said bar member in'clamping relationso that said bar member is fixed for rotative movement with said supportingmember but is at the same time slidable transversely of said supporting member, clamping members adapted to engage said piece of work, means mounting said clamping members on. said bar member, and means for moving said clamping members toward and from each other, the construction and arrangement of such mounting means and said last named means being such that upon movement of one ofsaid clamping membersv toward said piece of work, said other clampin member is equally moved toward said piece of work, whereby said clamping members exert equal clamping pressures on said piece of work.

3. A dog device adapted for attachment to the live spindle of a lathenaving a center point element in which said device clamps a piece of work which has been properly positioned on said center point element, comprising a supporting member adapted for driving attachment to said spindle, a bar member extending transversely of said supporting member, mean-s fixing the ends of said bar member on said supporting member against rotative movement with respect thereto but permitting transverse movement with respect thereto, clamping members, means mounting said clamping members on said bar member, and means for moving said clamping members toward and from each other, said last two named means being so constructed and arranged that when one of said clamping members is moved toward said piece of work the other clamping member is also equally moved toward said piece of Work, so that said clamping members engage said piece of work with equal pressures.

4. A dog device adapted for attachment to the live spindle of a lathe having a center point elemember "toward said supporting member, clampspect to each otheron said bar member.

5. A'dog device adapted forattachment to the live'spindle of a lathe havin fa center point element in which saiddevice clamps a piece of work which has been ;prope rlypositione d on said center point element, comprising'a supportingmember adapted for driving attachment to said spin- 'dle, a bar member, means resiliently urging said bar member toward said supporting member, clamping members slidably mounted on said bar member, means mounted on said bar member and engaging said clamping members for adjustably fixing said clamping members with respect to each other on said bar member, and releasable means for urging said bar member away from said supporting member against the action of said resilient means.

' 6. A dog device adapted for attachment to the 1ive spindle of a lathe having a center point elementin which said device clamps a piece of work which has been properly positioned on said center point element, comprising a supportin member adapted for driving attachment to said spindie, a bar member, means resiliently mounting said bar member with respect to said supporting member, clamping members slidably mounted on said bar member, means mounted on said bar member and engaging said clamping members for adjustably fixing said clamping members with respect to each other on said bar member, and cam means for urging said bar member away from said supporting member.

'7. A dog device adapted for attachment to the live spindle of a lathe having a center point element in which said device clamps a piece of work which has been properly positioned on said center point element, comprising a supporting member adapted for driving attachment to said spindle, a bar member, means resiliently mounting said bar member with respect to said supporting member, clamping members slidably mounted on said bar member, means mounted on said bar member and engaging said clamping members for adjustably fixing said clamping members with respect to each other on said bar member, and releasable means for urging said bar member together with said clamping members away from said supportingmember, whereby "upon release adapted driving'attachmentfto said spindle, j a bar member, meansresilientlyurging saidbar of said releasable means after said piece of work has been clamped, said piece of work is pulled against said center point element.

8. A dog device, adapted for attachment to the live spindle of a lathe having a center point element in which said device clamps a piece of work which has been properly positioned on said center point element, comprising a supporting mem'. ber adapted for driving attachment to said spindle, a bar member, means resiliently mounting said bar member with respect to said supporting member, clamping members slidably mounted I on said bar member, and releasable cam means for urging said bar member together'with said clamping members away from said supportingv member, whereby upon release of said releasable nve stmd eioranth navmg a center point ele- "ment inwhich said device clamps a piece of work which has been properly positioned on said center point element, comprising a supporting member adapted,- for driving attachment to said spindle, a *bar'member, mounting members disposedadja'cent the ends of said bar member, said bar member b'ei'ngmounted to said 'mounting members and said mounting members being piv- 10' pivot-ing about an'axis parallel to, that of said spindle, clamping members, means mounting said otally connected to said supporting member for clamping members on said bar member, and

meansfo'r moving said clamping members toward and from each other. I

10; A dog device adapted for attachment to the live spi'ndle'of a lathe having a; center'point element in which said device clamps'apiece of work which has been properly positioned on said center point element, comprising a supporting member adapted for driving attachment to said spindle, a bar member, mounting members disposed adjacent the ends of said bar member, said bar member being connected to said mounting members, means pivotally and resiliently mounting said mounting members on said supporting member such that resilient movement is permitted only in a direction parallelto the axis of rotation of the spindle, clamping members, means mounting said clamping members on said bar member, and means for moving said clamping members toward and from each other.

11. A dog device adapted for attachment to the live spindle of a lathe having a center point element in which said device clamps a piece of work which has been properly positioned on said center point element, comprising a supporting member adapted for driving attachment to said spindle, a bar member, mounting members disposed adjacent the ends of said bar member, said bar member being connected to said mounting members, means pivotally and resiliently mounting said mounting members on said supporting member, clamping members, means mounting said clamping members on said bar member, means for moving said clamping members toward and from each said mounting members, means resiliently and j pivotally connecting said mounting members to said supporting member, clamping members slidably mountedon said bar member, means mounted on said bar member and engaging said clamping members for adjustably fixing said clamping members with respect to each other on said bar member, and releasable cam means for urging said bar member together with said clamping members away from said supporting member against the action of the means which resiliently mount the mounting member with respect to the supporting member, whereby upon release of said releasable means after said piece of work has been clamped,

said piece of, work is pulled against said center p t e ement.

13. A dog device adapted for attachment to the live spindle of a lathe havinga center point element in which said device clamps a piece of. work which has been properly positioned on said center point element, comprising a supporting member adapted for driving attachment to said spindle, a bar member, mounting members disposed adja-- cent the ends of said bar member; means slidably mounting one end. of said bar'member to its adjacent mounting member, means slidable with respect to the other of said mounting members and slidably mounting the other end of said bar-membet, means pivotally mounting said mounting members with respect to said supporting member, clamping members mounted on said. bar member and means for moving said clamping. members toward and from each other to clampv and release said piece of work.

14. A dog device adapted for attachment to the live spindle of a lathe having a center point element in which said device clamps a piece of work WILLIAM J. NIGHTINGALE. 

